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Re: PMD Objectives


You had sent this table to me asking for my input before you sent it to the 
reflector in general.  I have not had time to do that before you sent it 
out.  I have some very specific issues with your table.  In the first 
place, as I have stated to you before, I do not believe that there will be 
a lot of patch panels in use except for extended distance and "riser" 
applications.  In situations where patch panels are used, the effective 
distance is greater because of the attenuation of the connectors in the 
patch panels.

What are you referring to as far as "Backbone + Equipment Cable"?  Other 
than a few building "riser" and campus applications, I see little use for 
the 300m distance objective.  WAN PHY (WIS) interconnections will either be 
at the < 50m distance or at the 10km distance, depending on whether it will 
be used with DWDM and/or Optical Switching.

I would expand the distance of all of your 30m applications to 50m.  The 
distinction should be between overbuilding existing data rooms with 10GbE 
which is very near term and the building of data rooms exclusively with 
10GbE which is more long term.

Thank you,
Roy Bynum

At 02:15 PM 8/9/00 -0400, Chris Diminico wrote:
>As I pointed out in e-mail to Jonathan, for completeness, we need to simply
>state all of the relevant application spaces and associated distances in
>order to address the applicability of the current set of distance objectives
>further the PMD discussion.
>The table attached is my attempt at characterizing the cabling distances
>10 Gb/s application space. The customer  premise cabling lengths are
>(by survey and reference). I am collecting information on the cabling
>lengths associated with
>the central office and the data center. The lengths provided for the data
>center and central office are reasonable target values which may be modified
>based on further study. Any help would be
>  Chris Di Minico
>Cable Design Technologies (CDT) Corporation
>Director of Network Systems Technology
>Phone: 800-422-9961 ext:333
>e-mail: cd@xxxxxxxxxxxxxx